Metal-containing nanoparticles, particularly metal oxide nanoparticles, have attracted a great deal of attention for their utility in numerous applications, including their use in electrode materials and as catalysts in various chemical reactions. There are currently known methods in the art for synthesizing hollow metal oxide nanoparticles and/or metal oxide nanoparticles having a core@shell structure. However, there remains a need in the art for a facile, effective method for producing well-defined, solid metal oxide nanoparticles with a controllable particle size.